THE MARSHMALLOW TEST AND decades of subsequent studies showed us that self-control ability early in life is immensely important for how the rest of life plays out, and that this ability in the young child can be assessed at least roughly on a simple measure. The challenge was then to untangle the underlying mental and brain mechanisms that let some children wait for what seems like an unbearable amount of time during the test, while others ring the bell within seconds. If the conditions that facilitate self-control, and those that undermine it, could be identified, perhaps they could be harnessed to teach people who have trouble waiting to be better at it.
I chose preschoolers for the research because watching the changes in my own children suggested that this was the age at which youngsters begin to understand the contingency. They can grasp that if they choose the smaller treats now it prevents them from getting the more preferred treats later. It is also the age at which important individual differences in this ability become clearly visible.
Many miracles seem to occur in the transformations from birth to crawling, talking, walking, and heading to preschool. No change was more remarkable to me than a child’s transition from distressed howling for help to being able to wait, sitting alone in a chair with nothing to do, for many boring and frustrating minutes in anticipation of two cookies. How do they do it?
A century ago, Freud thought the newborn began as a completely impulse-driven creature, and he speculated about how this bundle of biological instincts that urgently pushed for immediate gratification managed to delay gratification when the maternal breast was withdrawn. In 1911, he proposed that this transition became possible in the first couple of years of life when the infant created a mental “hallucinatory image” of the objects of desire—the mother’s breasts—and focused on it. In Freud’s language, the infant’s libidinal or sexual energy was directed at (“cathected onto”) this hallucinatory image. This visual representation, he theorized, allowed “time binding”; it enabled the infant to delay and temporarily inhibit the impulse for immediate gratification.
The idea that mental representations of the reward and its anticipation sustained the goal-directed effort to pursue it was provocative—but it was not obvious how to test it with young children long before imaging machines could peek into the human brain. We figured that the most direct way to get the young child to mentally represent the anticipated rewards was to let her see them while she waited for them. In the first experiments, the child chose the rewards she wanted and then the researcher placed them on top of an opaque tray in front of her, in clear view. In other conditions, the researcher placed them right under the tray so they were covered and obscured from view. At this age, the children understood that their rewards were really there, underneath the tray. In what condition do you think it was hardest for the preschoolers to wait?
You probably intuitively guessed right: when the rewards were exposed, the temptation was great and it was hellish for the kids to wait; when the rewards were covered, it was easy. Preschoolers who were exposed to the rewards (whether the delayed ones, the immediate ones, or both) waited on average less than a minute, whereas they waited almost ten times longer when the rewards were covered. Although in retrospect the results seem obvious, we needed to demonstrate them to be sure we had found a truly tempting, difficult-conflict situation.
I watched the children unobtrusively through the one-way observation window while they were trying to wait in the rewards-exposed condition. Some covered their eyes with their hands, rested their heads on their arms to stare sideways, or turned their heads away to completely avoid facing the rewards. Trying desperately to avert their gaze for most of the time, some occasionally stole a quick glance toward the treats to remind themselves that they were still there and worth waiting for. Others talked quietly to themselves, their barely audible whispers seeming to reaffirm their intentions through self-instructions—“I’m waiting for the two cookies”—or by reiterating the choice contingency aloud: “If I ring the bell I’ll get this one but if I wait I’ll get those.” Still others simply pushed the bell and the tray as far away from their faces and hands as they possibly could, right to the table’s outer edge.
Successful delayers created all sorts of ways to distract themselves and to cool the conflict and stress they were experiencing. They transformed the aversive waiting situation by inventing imaginative, fun distractions that took the struggle out of willpower: they composed little songs (“This is such a pretty day, hooray”; “This is my home in Redwood City”), made funny and grotesque faces, picked their noses, cleaned their ear canals and toyed with what they discovered there, and created games with their hands and feet, playing their toes as if they were piano keys. When all other distractions were exhausted, some closed their eyes and tried to go to sleep—like one little girl who finally dropped her head into her folded arms on the table and fell into a deep slumber, her face inches from the signal bell. While these tactics were a marvel to behold in preschoolers, they are familiar to anyone who has ever been trapped in the front row at a boring lecture.
When going on long car trips with young children, parents often help their preschoolers generate their own fun to make the trip go faster. We tried that in the Surprise Room: before the waiting period began, we suggested that the children think some “fun thoughts” while waiting and prompted them to come up with a few examples, such as “when Mommy pushed me on a swing and I went up and down, all high up and down.” Even the youngest children were wonderfully imaginative in generating their own fun thoughts when encouraged with a few simple examples. When happy thoughts were suggested before the researcher left the room, children waited for more than ten minutes on average, even when the rewards were exposed. Their self-generated fun thoughts counteracted the strong effects of exposure to the actual rewards, allowing them to wait as long as they did when the rewards were covered. They waited less than a minute when distracting thoughts were not primed. In contrast, cueing them to think about the rewards for which they were waiting (for example, “If you want to, while you’re waiting you can think about the marshmallows”) guaranteed that they would ring the bell soon after the door closed.
To get the participants closer to forming the mental images Freud might have had in mind, we showed the children pictures of the treats rather than the treats themselves. Bert Moore, then my graduate student at Stanford (currently dean of the School of Behavioral and Brain Science at the University of Texas at Dallas), and I exposed preschoolers to realistic, life-size photos of the treats they had chosen. The images were displayed on the screen of a slide projector box (which was the best technology of the time) that was placed on the table at which the children sat. If the child had selected marshmallows, for example, then she saw a slide-projected image of them while she waited.
Now we got a big surprise: the results were completely reversed. Exposure to the real treats had made delay intolerable for most, but here we learned that exposure to their realistic images made it much easier to wait. Children who were exposed to images of the treats waited almost twice as long as those who saw irrelevant images or no images on the lit screen, or those who were exposed to the actual treats. Importantly, the images had to be of the treats for which the child was waiting, not of similar goodies that were irrelevant to what the child had chosen. In sum, an image of the object of desire, not the tempting object itself, made it easiest to wait. Why?
I asked “Lydia,” a four-year-old girl with a smile-filled face, pink cheeks, and bright blue eyes, how she was able to wait the whole time, sitting patiently in front of the image of her treats. “You can’t eat a picture!” she answered, as she happily began to sample her two marshmallows. When a four-year-old stares at the marshmallows she wants, she’s likely to focus on their hot tempting features and ring the bell; when she sees a picture of them, it’s more likely to serve as a cool reminder of what she’ll get if she waits. As Lydia said, you can’t eat a picture. And as Freud might have thought, you can’t consume a hallucinatory representation of an object of desire.
In one condition of one of the studies, before the researcher exited, he said the following to children who were going to be looking at the real objects: “If you want to, when you want to, you can pretend they are not real, but just pictures; just put a frame around them in your head, like in a picture.” Other children saw the picture of the rewards but were cued to think about them as if they were real: “In your head, you can make believe they’re really there in front of you; just make believe they’re there.”
Facing pictures of the rewards, the children delayed 18 minutes on average—but when they pretended that the real rewards, rather than the pictures, were in front of them, they waited less than six minutes. Even when they faced the real rewards—the condition in which the average delay time is a minute or less—but imagined them as pictures, they could wait 18 minutes. The image they conjured up in their heads trumped what was exposed on the table.
More than half a century ago, the Canadian cognitive psychologist Daniel Berlyne distinguished between two aspects of any stimulus. First, a tempting, appetitive stimulus has a consuming, arousing, motivating quality: it makes you want to eat the marshmallow, and when you do it’s pleasurable. Second, it also provides descriptive cues that give information about its nonemotional, cognitive features: it’s round, white, thick, soft, edible. So the effect the stimulus has on us depends on how we represent it mentally. An arousing representation focuses on the motivating, hot qualities of the stimulus—the chewy, sweet quality of the marshmallows or the feel of the inhaled cigarette smoke for the tobacco addict. This hot focus automatically triggers the impulsive reaction: to eat it or smoke it. A cool representation, in contrast, focuses on the more abstract, cognitive, informational aspects of the stimulus (it’s round, white, soft, small) and tells you what it is like, without making it more tempting. It allows you to “think cool” about it rather than just grab it.
To test this idea, in one condition, before leaving the room, the researcher prompted the children to think about the hot, appetitive, appealing features of the rewards: the sweet, chewy taste of marshmallows. In a “think cool” condition, the children were prompted to think about the marshmallows as round and puffy clouds.
When cued to focus on the cool features of their rewards, children waited twice as long as when prompted to focus on the hot features. Importantly, when the child thought hot about the specific rewards for which he was waiting, it soon became impossible for him to continue to delay. But thinking hot about similar rewards for which he was not waiting (for example, pretzels while waiting for marshmallows) served as a splendid distraction and enabled an average of 17 minutes of delay. Children who just couldn’t wait when cued to think “hot” about what they wanted right now could easily wait when cued to think “cool” about it.
The emotions the preschoolers experienced also affected how soon they rang the bell. If we suggested before leaving them alone with their temptations that while waiting they might think of some things that made them sad (like crying with no one to help them), they stopped waiting as fast as if we had suggested thinking about the treats. If they thought about fun things, they waited almost three times longer: close to 14 minutes on average. Give nine-year-old children compliments (for example, on their drawings), and they will choose delayed rather than immediate rewards much more often than when given negative feedback on their work. And what holds for children applies to adults. In short, we are less likely to delay gratification when we feel sad or bad. Compared with happier people, those who are chronically prone to negative emotions and depression also tend to prefer immediate but less desirable rewards over delayed, more valued rewards.
The hotter and more salient the desired reward, the more difficult it is to cool the impulsive reaction to it. Researchers offered almost seven thousand fourth and sixth graders in Israeli public schools choices between alternatives that varied in reward amounts (one versus two), delay time (immediate versus one week, one week versus one month), and appetitive appeal (chocolate, money, crayons). Not surprisingly, they chose the delayed alternatives most often for crayons and least often for chocolates. As every dieter knows, the hotness of a temptation exerts its power as soon as the refrigerator is open or the waiter describes the desserts.
The power is not in the stimulus, however, but in how it is mentally appraised: if you change how you think about it, its impact on what you feel and do changes. The tempting chocolate mousse on the restaurant dessert tray loses its allure if you imagine a cockroach just snacked on it in the kitchen. Although Shakespeare’s Hamlet personified tragically unconstructive ways to appraise experience, he made this point insightfully: “There is nothing either good or bad, but thinking makes it so.” As Hamlet also showed, trying to change how we think about or “mentally represent” stimuli and experiences that have become deeply ingrained can be as futile as trying to be your own brain surgeon. How one might cognitively reappraise events more easily and effectively is the central challenge for cognitive behavior therapies—and for anyone seriously committed to trying to change well-established dispositions and habits. It is also the basic question pursued throughout this book.
The marshmallow experiments convinced me that if people can change how they mentally represent a stimulus, they can exert self-control and escape from being victims of the hot stimuli that have come to control their behavior. They can transform hot tempting stimuli, and they can cool their impact by cognitive reappraisal—at least sometimes, under some conditions. The trick is getting the conditions right. It doesn’t require Spartan clenched-teeth self-torture to toughen up and take the pain, but it does take more than strong motivation and the best intentions.
The power resides in the prefrontal cortex, which, if activated, allows almost endless ways of cooling hot, tempting stimuli by changing how they are appraised. The preschoolers, even with their immature frontal lobes, illustrated this with great imagination. They changed the temptations they faced into “just a picture” and put a frame around them in their heads; or shifted their attention away from temptations altogether through self-distraction, by inventing songs or exploring toes; or transformed them cognitively to focus on their cool and informative rather than hot and impulse-arousing features. When children transform marshmallows into puffy clouds floating in the air rather than thinking of them as delicious chewy treats, I have seen them sit in their chair with the treats and bell in front of them until my graduate students and I couldn’t stand it anymore.
We now knew that how children mentally represented external rewards predictably changed how long they waited. We also had learned in our other studies that children’s ability to delay gratification increased with age, as did the range of strategies they could use to enable it. But what did the young child know about the strategies that would or would not be useful for helping him wait long enough to get those treats? How did the child’s understanding of those strategies develop over time? Most important, did this understanding increase the ability to delay gratification?
My collaborators and I asked many children at different ages about the conditions, actions, and thoughts that would make it harder or easier for them to wait for their treats during the Marshmallow Test. None of these children had taken the test before, and they were introduced to it in the standard way. The child was seated at the little table, the selected treats were exposed on top of the tray, the bell was introduced, and the “one treat now or two later” contingency was explained. At this point, instead of leaving to let the child begin to wait, the researcher asked about the conditions that would help him or her wait. For example, “Would it be easier to wait if the marshmallows were on top of the tray so you could see them, or if they were under the tray so that you couldn’t see them?”
At age three, most children could not understand the question and did not know what to say. Four-year-olds understood what we were asking but systematically selected the worst strategy: they wanted to expose the rewards during the delay period and to think about them, stare at them, and focus on how good they would be to eat. When asked why they were exposing the rewards, they said “Because it makes me feel good” or “I just want to see it” or “It’s so yummy,” apparently focusing on what they wanted (“I like them”), not yet understanding, or caring, that seeing the rewards would make it most difficult for them to wait. They wanted what they were waiting for to be right there in front of their eyes. And by having the rewards exposed they defeated their own solemn intentions to wait, surprising themselves when they saw that they had rung the bell and grabbed the treat. They not only failed to correctly predict their behavior, but they insisted on creating the conditions that would make it impossible for them to get the delayed rewards. These findings may help parents understand why their four-year-olds can still have such a hard time controlling themselves.
Within a year or so the change in the children was striking. By age five to six, most preferred to obscure the rewards and consistently rejected arousing thoughts about them as a strategy for self-control. Instead, they tried to distract themselves from the temptation (“Just sing a song” or “I guess I’ll go to outer space” or “I think I’ll take a bath”). As they got older, they also began to see the value of focusing on the contingency and reiterating it (“If I wait, I can get the two marshmallows, but if I ring, I’ll get just one”). And they advised themselves with instructions: “I’ll say, ‘No, do not ring the bell.’ If I ring the bell and the teacher comes in, I’ll just get that one.”
“How should you wait for the marshmallows to make it easy?” I asked “Simon,” age nine. He gave me his answer in a drawing of someone sitting during the Marshmallow Test, with a thought bubble showing that he was thinking about “something I like to distract myself.” His additional written advice to me: “Don’t look at what you are waiting for—don’t think about nothing because then your [sic] thinking about it—Use what you have at the moment to entertain yourself.” In further conversation, Simon explained how he managed this. He told me: “I have at least a thousand imaginary characters in my head, like those little toy figures I have in my room, and in my imagination I just take them out and play with them—I make up stories, adventures.” Like Simon, other children his age can be wonderfully creative as they use their imaginations to entertain themselves and make the time pass quickly when they need to delay gratification in situations like the Marshmallow Test.
Most children did not seem to recognize the value of cool thoughts over arousing, hot thoughts until around age 12. By then, they usually understood that hot thoughts about the treats would defeat delay, whereas cool thoughts that transformed the marshmallows into puffy clouds, for example, would reduce their desirability and make it easier to wait. As one boy put it: “I can’t eat puffy clouds.”
The key question that drove this work was: does knowledge of the strategies that make delay easier also give the child—and the adult, for that matter—greater freedom from being controlled and pushed around by temptations and pressures they are trying to resist? We found the answer many years later in a study of boys with impulsivity problems who were living in a summer camp residential treatment program (described in Chapter 15). Those who understood strategies for delaying gratification waited longer on the Marshmallow Test than those who did not have this knowledge, and this was true even when the roles of age and verbal intelligence were controlled and removed statistically. It became clear that enhancing such understanding could become a goal for parents and teachers that might be fairly easy to achieve.
In the 1980s I reported some of the early findings from the Stanford follow-up studies at a leading behavioral science research institute in Europe. I talked about the correlations we found between seconds of waiting on the Marshmallow Test and outcomes in adolescence, including SAT scores. A few months later, “Myra,” a friend who was a senior researcher at the institute and had heard my talk, contacted me. She told me in all seriousness that she had some news that worried her. At age four, her son consistently refused to wait for more cookies (his favorites), no matter how hard she tried to get him to do so. An excellent scientist was misreading the meaning of the correlations I had reported. Myra was thinking, at least when it came to her son, that findings that were statistically significant and consistent for groups of children implied that if her child could not delay gratification on the measure she tried, it meant he faced a dire future.
When Myra calmed down, she of course realized how incorrectly she had interpreted the results: correlations that are meaningful, consistent, and significant statistically can allow broad generalizations for a population—but not necessarily confident predictions for an individual. Look at tobacco use, for example. Many people who smoke die early from tobacco-induced diseases. But some—indeed many—don’t. If Johnny in preschool waits for his marshmallows you know that he is able to delay gratification, at least in that situation. If he doesn’t, you can’t be sure what it means. It could mean that he wanted to wait but couldn’t, or simply that he had not used the bathroom before sitting down for the test. If a young child is eager to delay but finds herself ringing the bell, it’s worth trying to understand the reasons.
As discussed in later chapters, some children start low in delay ability and get better at it over the years, and some start out eager and able to delay and then show decreasing levels of self-control over time. The experiments at the Bing Nursery School demonstrated how mental representations of temptations can change and even reverse their impact on behavior. The child who can’t wait a minute can manage to wait for twenty when he changes his thoughts about the temptations. To me, that finding is more critical than the long-term correlations because it points the way to strategies that can enhance self-control ability and reduce stress. And advances in cognitive neuroscience and brain imaging in the last few decades have opened a window into the brain mechanisms underlying the ability to delay gratification. We can now begin to see how our thoughts can cool the brain when we most need to control our impulses.